Lt. Col. Joseph D. Vasco, who lobbied unsuccessfully recently for appointment as chief of the Prince George's County police, has applied for medical disability retirement.

Two other commanding officers, associates of Vasco who set up a controversial police unit with him in 1969 to catch convenience store robbers, are also planning to retire.

Vasco, 48, has been with the county police for almost 20 years. He is presently deputy chief in charge of criminal investigations.

Early in 1980, he was critically injured when his police cruiser spun out of control while he was coming home from a police officer's funeral. He crashed on a rural road near Upper Marlboro, and it took him three months to recover from injuries to the chest, including a severed bronchial tube.

"I have always had problems since the day the accident occurred," Vasco said yesterday. A review board decided at that time that he could retire because of his injuries, he said, but "it was by mutual agreement (with the department) that I decided to stay." Now, he says, he is "leaning very heavily" toward leaving.

In the resume that Vasco circulated while he was lobbying to become chief, he mentioned the accident but said that the injuries did not prevent him from working and that he had accumulated over a year of unused sick leave.

A county medical review board is considering Vasco's application for medical disability retirement and must make its recommendations to another county review board. If he is granted disability retirement, Vasco is entitled to 70 percent of his pay immediately upon retirement. If disability is denied, he would receive 56 percent of his pay. Vasco's current salary is around $50,000.

Vasco is widely respected by his fellow officers. Many of them thought he would be nominated to be chief by County Executive Parris N. Glendening, replacing Chief John E. McHale Jr. who is leaving early next month.

But last month, Glendening decided not to appoint Vasco after black community leaders objected to Vasco's role in the convenience store stakeouts. A series published by The Washington Post in 1979 revealed that 10 years earlier, Vasco headed a special police unit that helped informants set up robberies at convenience stores. Police killed two suspects in those robberies.

Last May a federal court jury acquitted Vasco and two other county police officers of any wrongdoing in those shootings. Also cleared in that trial was retired Maj. Blair Lee Montgomery and Capt. James E. Fitzpatrick, a 20-year veteran who, according to several police friends, is planning to retire at the end of the year and move to Florida.

Capt. Richard Shaner, who also worked with Vasco in the special police unit but who was not charged in connection with the shootings, is retiring at the end of this month. Shaner, a 21-year veteran on the force, is currently an evening duty commander. Shaner said yesterday that the decision not to name Vasco chief had nothing to do with his decision to move.

Shaner, 44, said he wants to move to a warmer climate--in Louisiana--where he may sell hunting and fishing equipment.

Vasco quietly began to campaign for the chief's job after the federal trial ended and said privately that he was quite disappointed when he was not named to the post.

Glendening nominated Maj. Michael J. Flaherty to replace McHale. Flaherty is expected to be confirmed by the county council next week.

Vasco said earlier this week that some officers who have worked under him have offered "thoughtful words" and tried to encourage him to stay. Other colleagues, he said, are urging him to retire from the department that has passed him over.

He has not made specific plans for new employment, he said, though "I have been talked to by a couple of people about jobs outside of police work."

No matter what, he says, he will continue to live in the south-county area of Croom.

Vasco currently owns no private businesses, according to financial statements on file with the county. During the 1970s, he had an interest with Shaner in an Ohio oil well. He also had a one-third interest in Scientific Interviews, Inc. a lie detector company, at one time.